Accelerators of vulcanization



Patented Aug. 4, 1936 PATENT. OFFICE 2,050,195 ACCELERATORS OF VULCANIZATION Lorin B. Sebrell Silver Lake, Ohio, assignor to Wingfoot Corporation, Wilmington, Del., a cor-,

poraticn of Delaware No Drawing. Application March 1, 1932, Serial No. 596,145. Renewed January 25, 1934 2 Claims.

This invention is predicated upon the discovery that when the mercapto aromatic thiazoles are reacted with the primary aliphatic monamines, particularly those which are completely satu rated, the reaction products so obtained, constituting newcompounds in and of themselves, are vulcanization accelerators of marked value, being in many cases even more powerful than the thiazoles from which they are derived. These mercaptobenzothiazole or its derivatives are often relatively easily decomposed when incorporated in rubber. For that reason, these materials are not adapted for milling into solid rubber in the ordinary processes of manufacturing such stocks as those employed in vehicle tires and tubes. These relatively volatile compounds may, however, be readily employed as accelerators in rubber cements and compounded latices.

1O As has been pointed out above, these materials subtances y be obtanled by f' are readily obtained by adding one mol. of the ped1ent 0f addmg desired pnmary ahphatm desired primary aliphatic monamine to an alcomonamme m of the desn'ed mercapto holic solution of one mol. of the desired mercapto aromatic thiazole in alcohol or other solvent at aromatic thiazole at normal room temperatures normal room temperature$- (approximately 35 degrees 0.). The reaction 15 The following are illustrative am s of product crystallizes out of the alcohol in relam p aromatic thiazoles wh h y be tively pure form. In the case of the cyclohexyl ployed: mercaptobenzothiazole, Z-mercapto 4- ammonium benzothiazyl mono sulphide obtained phenyl thiazole, 6-methyl mercaptobenzothiazole, from the cyclohexyl amine and mercaptobenzo- 5 or 6-chloro mercaptobenzothiazole, 2-mercapto thialole as above indicated, the product Separates 2O 4 1 mrcaptobenzothjazole and $-amido as white crystals, having the melting point of mercaptobenzothiazole. Completely saturated 155 F 157 degrees T normal buty1 primary aliphatic monamines with which such momum s'mtro benzothlflzyl mono sulphlfie 1s mercapto aromatic thiazoles will react are, for t i i {g fig g$:% havmg m p propyl amine heptyl amine iso butyl alie f llowing is an examp le of a formula in 25 cyc.1OheXy1 ethyl ether yc19heXy1 which reaction products other than those ob= amme lsoamylamme and normal; butyl m fl tained from the more volatile primary aliphatic In the reaction of these primary aliphatic monamines may be employed 3O monamines with mercapto aromatic thiazoles, Parts the nitrogen atom of the amino group is ap- Rubber 100 parently added directly to the sulphur in the merzinc oxide 5 captan group. For example, the reaction be- Sulfur 3 tween butyl amine and mercaptobenzothiazole stearic acid 1.5

may be expressed as follows: Accelerator .5 35

That between cyclohexyl amine and mercapto- To test the value of these new materials as benzothiazole may be represented in the following accelerators, samples prepared in accordance manner: with the above formula were subjected to vulcani- 45 Inasmuch as certain primary aliphatic monzation for varying periods of time. These amines, such as propyl amine, are relatively volasamples were then subjected to physical tests to tile in nature, the reaction products thereof with ascertain the elasticity and tensile strength 55 thereof, the results of a few of these tests being indicated in the following tables:

Stress in Cum kgsJcm. at

Time in Temp. Kgs/cmfi Percent 500% 700% mins. F. tensile along. elong. elong.

Cycle hearyl ammonium benzotluiazyl mono sulp e Butt/Z ammonium benzothiazyl mono sulphide Butylrammonz'um G-nitro bcnzcthiaz /Z mono i sulphide From this it will be seen that these materials are powerful accelerators which, when used in rubber, give rise to compounds of great tensile strength, elasticity and durability. Further, such materials are substantially non-toxic when employed in the amounts used in rubber stocks. They are also very readily prepared.

It will be understood that the details of the invention may be varied within comparatively wide limits without departing from the inventive concept and that it is therefore desired to embrace within the scope of this invention such modifications and changes as may be necessary to adapt it to varying conditions and uses. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside in the invention.

What I claim is:

1'. As a new chemical compound, N-cyclohexyl ammonium benzothiazyl mono sulphide. 2. As a new chemical compound, a primary cyclohexyl ammonium benzothiazyl mono sulphide.

LORIN B. SEBRELL. 

